Here are the essential concepts you must grasp in order to answer the question correctly.
Differentiability
A function is differentiable at a point if it has a defined derivative at that point, meaning the function's graph has a tangent line that is not vertical. This requires the function to be smooth and continuous at that point, without any sharp corners or cusps. If a function is not differentiable at a point, it may be due to discontinuities or abrupt changes in direction.
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Continuity
A function is continuous at a point if the limit of the function as it approaches that point equals the function's value at that point. This means there are no breaks, jumps, or holes in the graph at that point. For a function to be differentiable at a point, it must first be continuous there; however, continuity alone does not guarantee differentiability.
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Closed Interval
A closed interval, denoted as [a, b], includes all the numbers between a and b, including the endpoints a and b themselves. In the context of differentiability and continuity, analyzing a function over a closed interval allows us to evaluate its behavior at the endpoints and within the interval. This is crucial for determining where the function is differentiable or continuous.
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Improper Integrals: Infinite Intervals